Field of the Invention
The invention relates to a valve for regulating the flow of fluid. The valve may be used as a dump valve in a high pressure fluid system to relieve pressure when desired. It can also be used in any fluid system to provide an extremely tight seal with virtually no leakage, a condition sometimes referred to as a “bubble tight seal.”
Background of the Invention
A bubble tight seal is very desirable, and in some cases required, for pressure decay testing. Currently available technology utilizes highly polished metal to metal seat assemblies, or grease injectable sealing features. Valves using highly polished seat assemblies, can be made to have very small leaks, but not “bubble tight.” Additionally these valves are very susceptible to damage of their highly polished seat assemblies. Another current technology utilizes precision seat assemblies, not highly polished, and a special grease that seals the imperfections of the precision seat assemblies. These valves work as “bubble tight” but required constant greasing to keep them operating properly.
When performing a hydrostatic test it is normally a requirement to have a rupture disc in fluid communication with the high pressure fluid that has a rupture rating of not more than 1.5 times the specified hydrostatic test pressure. This is a difficult requirement for most hydrostatic test system to comply with. To comply you are required to dissemble the rupture disc body, remove the currently installed rupture disc, replace it with the appropriate rupture disc, and then reassemble the rupture disc body. Additionally, the old certification tag must be removed from the rupture disc body and the new tag installed. Having the certification tag separately attached, usually by a safety wire, can be problematic. This system can lead to a rupture disc that is not properly identified because it is permanently attached to the rupture disc body.
Consequently there is a need for a valve that is not highly susceptible to damage and that does not require constant greasing for proper operation, also there is a need for a simple and less burdensome manner for certifying that a correct burst disc was utilized during the testing process.